Dramatic changes in chemical composition, metabolism, and organization of cell-surface glycosphingolipids characterize a common membrane phenotype associated with oncogenic transformation. Recent studies with monoclonal antibodies directed to various human cancers have revealed unusual accumulations of certain glycolipids in human cancer, such as GD.sub.3 ganglioside in human melanoma, Gb.sub.3 in Burkitt lymphoma, sialosyl-Le.sup.a ganglioside in colorectal, gastric, and pancreatic cancer, and 6C fucoganglioside (VI.sup.6 FucIII.sup.3 NeuAcnLc.sub.6) in colorectal and hepatic cancer. For a review, see Hakamori, S., et al., J.Natl.Cancer Inst. 71: 231-251, 1983. More recently, accumulation of glycolipids with di- or trifucosylated type 2 chain has been found in a large variety of human cancers (J.Biol.Chem. 259: 4672-4680, 1984), and monoclonal antibodies that can distinguish di- and trifucosylated type 2 chain from monofucosylated type 2 chain have been established (J.Biol.Chem. 259: 4681-4685, 1984). One of the antibodies, FH4, specifically reacts with the antigen having difucosylated type 2 chain, which is common in a variety of gastrointestinal and colorectal adenocarcinomas, but is restricted to a few types of cells in normal human gastrointestinal and urogenital epithelial tissues. Other studies of the gangliosides of human adenocarcinoma have shown an accumulation of a large quantity of sialosyl 2.fwdarw.6 lactoneotetraosylceramide (J.Biol. Chem. 258: 11819-11822, 1983) and other more complex novel fucogangliosides, termed gangliosides 6B and 6C (Biochem.Biophys.Res.Commun. 113: 791-798, 1983). It would be advantageous to isolate and identify the 6B ganglioside and to raise a hybridoma antibody defining this structure and establish its specificity and reactivity in normal and transformed tissue.